Patent GB-132395-A (GB)
IPC: G11B3/08
Abstract: 132,395. Mitchell, F. B. Nov. 14, 1918. Returning sound-box to starting-point; starting and stopping; disk records.-Relates to automatic repeating and stopping devices for disk machines of the class described in Specifications 103,523 and 113,863, and consists in providing a stopmember adjustably positioned near the rim of the turntable and adapted to take up a new position after being struck by the sound-box after each reproduction, until eventually, after the desired number of reproductions, it stops the tone-arm with the friction block still on the record, thus arresting the machine. The return of the tonearm may be assisted by a weight. Means are provided for adjusting the position of the friction block, and for attaching a shoulder to the central portion of the record. In the form of the invention shown in Figs. 1 and 2, the stop-member S is carried on an arm A loosely pivoted on a pin D. A pin A<1> on the arm A engages a short slot in an arm B which is mounted friction-tight on the pin D. A brake B<3> holds the turntable when the arm A is swung into the position shown in dotted lines. When the arm A is moved to the operative position, a lug A<5> strikes the record rim, and the removal of the brake B<3> allows the machine to start. The lost-motion connexion A' allows the lug A<5> to disengage from the record rim, a light spring being provided, if necessary, to remove the lug from rubbing contact. The stop S comprises a hollow cylinder enclosing an eccentric weight W, Fig. 8, and is mounted to turn on, and to slide along, a central pin A<3> projecting horizontally from an ear A<2> on the arm A. On its underside, the stop S has a stepped slot, shown in Fig. 6, with which engages a vertical pin A' on the arm A. A stepped tappet S<1>, S<2>, S<3>, Figs. 6 and 8, projects from the face of the stop S towards the turntable centre. As shown, the stop is adapted to arrest the machine after the third reproduction, the stop S being adjusted before starting so that the pin A' engages the end S<8> of the slot. At the end of the first reproduction, the sound-box R is returned to the record rim as described in the prior Specifications, and strikes the shoulder S' of the tappet, pushing the stop S axially along the pin A<3> until the pin A<4> reaches the corner S<7> of the stepped slot. The friction block G<2> then falls over the record rim, and the stylus re-engages the starting-groove for the second reproduction. The weight W then rotates the stop S, bringing the pin A<4> to the corner S<6> of the slot. At the end of the second reproduction, the sound-box is again returned and strikes the shoulder S<2> and moves the stop S until the pin A<4> reaches the corner S<5>, and the stylus again engages the record for beginning the third reproduction. The stop S is again rotated by the weight W, bringing the pin A<4> to the point S<4>. When the sound-box returns at the end of the third reproduction, it strikes the end S<3> of the tappet, and, as the stop S is no longer free to move axially along the pin A<3>, the friction block G<2> remains on the record surface and arrests the machine. A modified form of apparatus, Figs. 16 and 19, is arranged to give one repetition only before arresting the machine. The tappet C is carried on a spring C<4> which elevates the tappet to the position shown in Fig. 16, unless it is held down by a hook C<3> projecting through a slot B<1@> in an aim B<10> mounted friction-tight on a pin D. The spring arm C' is loose on the pin D. At starting, the hook C<3> is engaged as shown in Fig. 19, and the sound-box R returning after the first reproduction, strikes an upstanding tooth C<2>, moves the tappet C outwards, and releases the hook C<3>. The friction block thereupon falls over the record rim, and the stylus engages the starting-groove of the record. When the sound-box is again returned to the rim, it strikes the end C' of the tappet C, which has been elevated by the spring C<4>, and is then locked against further movement. In consequence, the friction block remains on the record and stops the machine. The initial setting of the stop is effected by a knob B" the stem of which has a slight sliding movement in a socket on the arm B<10>, the opposite end ot the plunger being placed in contact with the record rim. The stop-member may be arranged to slide radially to the record during initial adjustment, instead of being mounted on a pivoted arm. The lost motion required to remove the setting- member from contact with the record rim may be effected by gravity. The shoulder K, Fig. 20, by which the friction block is brought into action may be secured to the record face by an adhesive printed label T, which may have attached a strip of paper of definite length so that the shoulder may be secured at the required distance from the innermost record groove. The weight for assisting the return movement of the tone-arm is suspended bv a cord and may rest on a ledge during part of the reproduction, the return movement being started by the weight and completed by the momentum of the tone-arm. The friction block G<2>, Fig. 1, may be carried on a cranked vertical spindle, which may be turned in its supporting socket for adjusting the position of the block.